Dental chair.



F. RiTTER.

DENTAL CHAIR.

APPLICATION FILED NOV. 14, 1911.

Patented May 4, 1915.

4 SHEETS-SHEET 1- a vwemto o F. BITTER.

DENTAL CHAIR.

APPLICATION FILED NOV. 14. 19M.

1,137,903. Patent-ed May 4, 1915.

4 SHEETS-SHEET 2.

gnvemtoz 3 THE NORRIS PETERS 60.. PHOTO-LITHCL, WASHINGTON. D. c

F. BITTER.

DENTAL CHAIR.

Patented May 4, 1915.

' 4 SHEETS SHEET 3.

F. BITTER.

DENTAL CHAIR.

APPLICATION man NOV. 14, 1911..

1,13?,903 Patented May 4, 1915.

4 SHEETS-SHEET 4.

\ L LIV/II) FRANK BITTER, OF ROCHESTER, NEW YORK.

DENTAL CHAIR.

Application filed. November 14, 1911.

To all whom it may concern Be it known that I, FRANK BITTER, of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Dental Chairs; and I do hereby declare the following to be a. full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference numerals marked thereon.

My present invention relates to chairs, particularly to the type usually employed for dentists, barbers and surgeons use, which in the broad aspect embody a seat frame and a back adjustable in different angular relations to the seat frame, and it has for its object to provide an improved construction and arrangement of parts whereby the body of the occupant will adjust itself readily for all positions of the chair so that the occupants back, head and shoulders are naturally positioned and supported comfortably at all times, thebody accommodating itself without exertion to the chair back as the latter is adjusted from an upright to an inclined or horizontal position.

A further object of my invention is to arrange a back rest on the chair back in such a manner that the back rest will be automatically adjusted with relation to the occupant, so that as the chair back rest is lowered, the back rest is raised more or less against the lower part of the occupants back a so fioient distance to support the back in a: natural position at any angle, and to conform to the. free movement of the body.

Another object of my invention is to afford a novel means for locking the chair back at any desired angle with relation to the seat frame, so that the chair structure is braced and rigidly held in any position, overcoming any tendency of the parts to become strained or sprung when heavy pressure is applied to the chair back.

To these and other ends the invention consists in certain improvements and comb-inations of parts all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings: Figure 1 is a view in side elevation, with parts appearing in vertical section, of a portion of a dental chair embodying a preferred arrangement of parts according to my present invention; Fig. 2 is Specification of Letters Patent.

Patented May 4, 1915.

Serial No. 660,232. I

a rear elevation of the back rest; Fig. 3 is a detail view illustrating the adjusting means for changing the position of the back rest relatively to the back; Fig. 4 is a rear elevation of the parts shown in Fig. 1; Fig. 5 is a side elevation of the chair, showing the back and parts carried thereby in an in clined position with respect to the seatframe; Fig. 6 is a similar view, disclosing a slightly modified arrangement of the parts; Fig. 7 is an enlarged detail view in elevation, showing the compensating device removed, the post, and the clutch cooperating therewith; Fig. 8 is a transverse sectional view on the line w:z: of Fig. 7 Fig. 9 is a vertical sectional View on the line 3 -g of Fig. 8; Fig. 10 is a sectional view illustrating the application of the clutch to the modified construction shown in Fig. 6; Fig. 11 is a sectional view on the line aa, of Fig. 10; Fig. 12 is a sectional view on the line Z2'b of Fig. 11.

Similar reference numerals throughout the several figures indicate the same parts.

In the present embodiment ofthe invention, the preferred form and arrangement of the several parts is shown as applied to a dental chair comprising the seat frame 1 carrying standards 2 on which is pivotally supported the back 3, the latter having the forwardly extending arms 4 which are pivoted on the standards 2 before mentioned. The back 3, it will be noted, is formed solid at its central portion, similarly to the usual dental chair back, and is provided on its rear face with an undercut portion 5 (Fig. 4) within which travels an adjustable carrier 6, movable upwardly or downwardly on the back to any desired position and held fixed by a suitable clamp. Adjustably mounted on the carrier 6 is the head rest 7 supported on the slide 8, which is held on the carrier 6 by a clamping mechanism adapted to permit its universal adjustment. The head rest may be of the usual or any preferred construction, and in its operation it combines v it is properly adjusted to the perfect comfort of the occupant of the chair.

In chair structures of the general type hereinbefore referred to, great difficulty has been experienced owing to the fact that when the back is tilted on the seat frame the back rest drops away from the occupants back, requiring him to shift hisposition and readjust his body for each new position of the chair, or a readjustment of the back rest and head rest, and in my present invention, I have overcome this inconvenience by providing means for automatically changing the position of the back rest with relation to the chair back. The arrangement of the partsof the chair are such that as the angular position of the chair back is changed relatively to the seat frame, the back rest is raised with respect to the lower portion or waist line of the back of a person seated in the chair thereby giving the proper support to the body as its position is changed. To this end, in the present embodiment, there is provided on the chair back, the part 11, pivoted at 12, which for convenience in description, is hereinafter referred to as the compensating device, in which sense it acts upon the back rest as the chair back is lowered or raised on the seat frame. The compensating device 11 is recessed as shown at 13 and 14, and is provided on opposite sides of the last mentioned recess 14 with suitable openings adapted to receive the post 15 which is pivotally mounted on the seat frame at 16. The pivotal point of the post 15 is preferably positioned relatively to the pivotal points of the arms 4, as shown in Fig. 1, being arranged in rear of the seat 17 and below the pivotal points of the chair back on the arms 2 and they point of connection, or between the compensating device and the chair back.

The arrangement of the parts just described may be varied without departing from my invention, although I have found that the best results are to be obtained when the parts are mounted relatively as herein disclosed.

The back rest 9 carries a pivotally mounted brace 18 which is provided with the roller 19 engaging the front face of the compensating device 11, and with the notched portion 20, with which cooperates the pawl 21 mounted on the back rest, for the purpose of supporting the latter at various positions of angular adjustment relatively to the compensating device. The pawl 21 preferably carries hand pieces 22 by which it may be conveniently operated. By this brace and pawl the back rest may be adjusted in the first instance to accommodate the body of the person seated in the chair when in a vertical position, and the arrangement is such that the parts occupy the smallest possible space, and permit the back rest to be adjusted quite closely to the compensating device, when desired, as shown in Fig. 1.

In order to retain the back of the chair in any adjusted position with relation to the seat frame, I prefer to lock the compensating device against movement on the cooperating element employed for effecting its adjustment relatively to the chair back, and to this end, I provide a clutch mounted on the compensating device and arranged to en-' gage the post. The clutch illustrated comprises the split member, or clamp 23 surrounding the post 15' and having jaws 24 and 25. The jaw 25 is slotted and pivotally arranged in said slot is the actuating member 26, the opposite end 27 of which is supported in a recess in the compensating device, so as to permit a swinging or pivotal. movement of. the clamping member relatively to its support. The clamp actuating member 26 carries the depending extension 28, arranged adjacent to the 24 said extension being preferably split and threaded to receive a setscrew 29, adapted to cooperate with the aw 24 to force it in a direction to close the clamping member. The set screw may be adjusted within the extension 28 to obtain the proper degree of pressure against said aw, and vary the clamping action of the clutch when necessary and is 'held in place by the additional set screw 30.

The clutch is held normally in looking position with relation to the post by means of a spring 31 which is held in a suitable recess in the compensating device by means of a threaded plug 32. The clutch may be releasedin any suitable manner, and to this end, in the present embodiment, there is provided a lever 33 which is pivotally supported in the ears 34 formed on the compensating device, and is arranged to engage the split nut so as to move the latter against the action of the spring 31, and release the parts. The lever 33 is held in normal position,

' against the split nut and ready for opera tion, by means of a suitable spring In order to prevent the post 15 from being withdrawn entirely from the compensating device, Ipreferably form thereon the head 36 arranged to be engaged by a spring pressed pin 37, the latter being suitably housed in a recess in the compensating de vice and held in operative position by means of spring 38 and the threaded plug 39.

It will be seen from the construction just described, that, normally, the compensating device is locked on the post 15, and the back thereby held in fixed position. To lower the back, a slight pressure is exerted upon the lever 33 which instantly releases the clutch and permits the back to be lowered by its own weight until the lever is released, the parts being thereupon instantly relocked. As the back is lowered, the compensating de vice is moved away therefrom by reason of the different pivotal points of the respective parts, and a corresponding movement is communicated to the back rest. In this manner, while the back and head rest are swinging about their fixed point of rotation, the back rest is swinging about the same point and at the same time is being moved on its own pivot relatively to the back and head rest, so that it is raised with respect to the lower part of the persons back as the chair back is lowered on the seat frame.

In Fig. 6, I have shown a slight modified form of the invention in which the clutch is mounted on the seat frame and cooperates with a post pivotally arranged on the back of the chair. Referring to Figs. 6, 10, 11 and 12, the chair back carries a post 40 pivctally mounted thereon and engaging the split clamp 41 which forms part of a clutch, constructed similar to the one already described, and mounted in a frame 42, which is pivotally supported on trunnions 43, the latter being carried by lugs 44:, mounted on, and preferably forming a part of the seat frame. The operation of the clutch included in this form is substantially the same as of the parts already described and no further description is therefore necessary.

Other changes and modifications of the invention may be had without departing from the underlying features of the invention herein described and claimed, and it is tobe understood that I am not limited to the precise construction disclosed, but intend to cover by this application any departures that may come within the scope of the claims hereinafter.

I claim as my invention:

1. In a chair, the combination with a seat frame, of a back rotatable on the seat frame, a back rest mounted on the back, and a compensating mechanism also mounted on the back between it and the back rest, and having connection with the seat frame, said compensating mechanism being operatively associated with the back rest whereby the lower end of the back rest is moved toward and away from the back to change the inclination of the back rest relatively to the back as the angular position of the latter is changed relatively to the seat.

2. In a chair, the combination with a seat frame and a back frame rotatable from an upright to an inclined position relatively thereto, of a back rest carried by the back frame and a compensating mechanism for moving the back rest outwardly from the back frame when the latter is lowered, said compensating mechanism comprising telescoping members swingingly connected to the seat and back frame.

3. In a chair, the combination with a seat frame and a back frame rotatable from an upright to an inclined position relatively thereto, of a back rest carried by the back frame and a compensating mechanism comprising telescoping members swingingly connected to the seat and back frame operat ing to move the back rest outwardly from the back frame when the latter is lowered and devices for clamping said telescoping members together to lock the back frame in its angular position of adjustment.

4. In a chair, the combination with a stationary seat, of a back rotatable relatively to the seat, a back rest mounted on the back, and a compensating mechanism disposed be tween the back and the back rest and connected to the back and seatand operating to incline the back rest angularly relatively to the back as the angular position of the latter is changed relatively to the seat.

5. In a chair, the combination with a seat frame, 'of a back adjustable on the seat frame, a back rest mounted on the back, and

a compensating device also mounted on the back, the compensating mechanism comprising members slidable on each other and swingingly connected to the seat frame and operatively associated with the back rest whereby the back rest is moved relatively to the back as the angular position of the latter is changed.

6. In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a post supported on the seat frame, a compensating device mounted on the back and arranged to control the position of the back rest, the compensating device having slidable engagement with said post, and a clutch for retaining the compensating device against downward movement on the post.

7. In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a post'supported on the seat frame, a compensating device mounted on the back and arranged to control the position of the back rest, the compensating device having slidable engagement with said post, a clutch acting normally to retain the compensating device against downward movement on the post, and means for releasing the clutch to permit free relative movement of the compensating device and post.

8. In a. chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a post supported on the seat frame, a compensating device mounted on the back and arranged to control the position of the back rest, a split clamp arranged on the post, and an actuating member pivotally supported on the compensating device and adapted to cooperate with the jaws of said clamp.

9. In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a post supported on the seat frame, a compensating device mounted on the back and aring connected to one jaw of the clamp and arranged to engage the opposite jaw thereof so as to retain the compensating device against downward movement on the post.

10. In a chair, the'combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a postsupported on the seat frame, a compensating device mounted on the back and arranged to control the position of the back rest, a split clamp arranged on the-post, and an actuating member supported on the compensating device, the actuating member being pivotally connected to one jaw of the clamp and provided with an extension arranged adjacent to the other jaw of said clamp, and a set-screw adjustable in the eX- I tension and adapted to engage the last mentioned jaw.

11, In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a post supported on the seat'frame, a compensating device mounted on the back and arranged to control the position of the back rest, a split clamp arranged on the post, an actuating member pivotally supported on the compensating device, the actuating member being pivotally connected to one jaw of the clamp and provided with an extension arranged adjacent to the other jaw of said clamp, a set-screw adjustable in the extension and adapted to engage the last mentioned jaw, a spring for moving the clamp normally in one direction, and a lever pivoted on the compensating device and adapted to move the clamp in the opposite direction to release the compensating device. 12. In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a compensating device mounted on the back and arranged to control the position of the back rest, and means for locking the back relatively to the seat frame comprising a split clamp engaging apost mounted on one of said parts, and an actuating member pivotally connected to one jaw of the clamp and pivotally supported on the other of said parts, the actuating member being ar- C'opies of ranged to engage the other jaw of the clamp.

13. In a chair, the combination with a seat frame, of a back adjustable on the seat frame, a back rest mounted on the back, a compensating device mounted on the back and arranged to. control the position of the back rest, and means for locking the back relatively to the seat framecomprising a split clamp engaging a post mounted on one of said parts, and an actuating member piva pivoted lever adapted to move it in the opposite direction to release the parts.

14; The combination with a post and a device slidable thereon, of a split clamp arranged on the post, and an actuating member pivotally connected to one jaw of the clamp and to said slidable device and also arranged to engage the other jaw of the clamp.

.15. The combination with a post and a device slidable thereon, of a split clamp arranged on the post, an actuating member connected to one jaw of the clamp and pivotally supported on said slidable device and provided with an extension arranged adjacent to the other aw of said clamp, and a bolt adjustable in the extension and adapted to engage the last mentioned 16. The combination with a post and a device slidable thereon, of a split clamp arranged on the post, an actuating member connected to one jaw of the clamp and pivotally supported on. said device and provided with an extension arranged adjacent to the other jaw of the clamp, a set-screw adjustable in the extension and adapted to engage said last mentioned jaw, a spring for moving the clamp normally in one direction, and a lever pivoted to said slidable device and adapted to move the clamp in the opposite direction.

FRANK BITTER.

lVitnesses: V

G; WILLARD R1011, RUssELL B. GRIFFITH.

this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0." 

